fix: added missing CSS unit when positioning the window offset to `top`

[emeraldsanto]

Description

This PR simply adds the missing px unit to the calculation of how much to offset from top. Without this, certain browsers will simply interpret the value as 0 which makes the page scroll to the top.

[topolanekmartin]

On mobile iOS it does not attach top property on body element. This causes the scroll is not returned back to its previous position after scroll is enabled.